encoding: add option to escape non-ascii characters in JSON This is necessary for hgweb to embed JSON data in HTML. JSON data must be able to be embedded in non-UTF-8 HTML page so long as the page encoding is compatible with ASCII. According to RFC 7159, non-BMP character is represented as UTF-16 surrogate pair. This function first splits an input string into an array of UTF-16 code points. https://tools.ietf.org/html/rfc7159.html#section-7

encoding: initialize jsonmap when module is loaded This makes jsonescape() a thread-safe function, which is necessary for hgweb. The initialization stuff isn't that slow: $ python -m timeit -n1000 -s 'from mercurial import encoding as x' 'reload(x)' original: 1000 loops, best of 3: 158 usec per loop this patch: 1000 loops, best of 3: 214 usec per loop compared to loading the commands module: $ python -m timeit -n1000 -s 'from mercurial import commands as x' 'reload(x)' 1000 loops, best of 3: 1.11 msec per loop

encoding: change jsonmap to a list indexed by code point This is slightly faster and convenient to implement a paranoid escaping. $ python -m timeit \ -s 'from mercurial import encoding; data = str(bytearray(xrange(128)))' \ 'encoding.jsonescape(data)' original: 100000 loops, best of 3: 15.1 usec per loop this patch: 100000 loops, best of 3: 13.7 usec per loop